Internal combustion engines, in which the injection control is not mechanically linked to the engine position, also require a phase sensor in addition to the crankshaft angle sensor on the crankshaft, the phase sensor being in synchronization with the camshafts, with which it is possible to determine which of the cylinders next to reach top dead center (TDC) is in a power stroke at the moment. This is known as the synchronization function. To be able to carry out the synchronization function as rapidly as possible, these sensor wheels are configured as fast-start sensor wheels, i.e., as sensor wheels with which a unique position is recognizable after an angle of rotation of approximately 90 degrees (=180 degrees crankshaft). A fast-start capability of the internal combustion engine is ensured in this way. In the event of a failure of the crankshaft sensor, an emergency operation capability or an emergency operation functionality of the internal combustion engine is ensured, in that the crankshaft angle is made available via the camshaft signal. The camshaft signal must therefore be analyzable exclusively on the basis of the time stamp of the camshaft flanks and must ideally have one tooth flank per cylinder of the internal combustion engine, each being the same distance from top dead center (TDC) of the cylinder. In internal combustion engines having camshaft adjustment, the prevailing positions of the camshafts are additionally ascertained by comparing the position of the equidistant tooth flanks on the camshaft sensor wheels, in relation to the crankshaft. This is known as ascertaining the camshaft adjustment position.
In today's camshaft position sensor wheels, these four functions are implemented in a single sensor wheel configuration with corresponding compromises. In fast-start sensor wheels for diesel engines and gasoline engines, at most four equidistant tooth flanks per camshaft revolution are available for ascertaining the camshaft adjustment position. During emergency operation, only these four flanks are utilized with conventional systems since the use of additional active tooth flanks would bring a disproportionate increase in system complexity in comparison with the benefits. In 4-cylinder engines, one item of camshaft position information is thus available per cylinder. However, camshaft position information is not evenly distributed in engines having 3, 6 or 8 cylinders, which entails an increased tolerance in the accuracy of the calculated camshaft position and thus in the filling of the cylinder and in the exhaust gases of the internal combustion engine during both normal operation and emergency operation. So-called Z+1 camshaft position sensor wheels utilize one active tooth flank per cylinder of the internal combustion engine and one additional active tooth flank for ascertaining the phase information of the internal combustion engine. These sensor wheels represent the optimized emergency operation capability but are not suitable for a fast start. They offer only one item of position information per cylinder in the distribution of the camshaft adjustment position information.